The invention disclosed and claimed herein generally pertains to a surgical instrument of a type which may be inserted into and operated within a body cavity or passage of a patient, wherein the cavity or passage is very narrow and spatially confining. More particularly, the invention pertains to an instrument of such type which is especially well suited for use in breaking apart the nasal septum from its attachment to the sphenoidal sinus wall in order to provide an opening therethrough. Even more particularly, the invention pertains to an instrument of such type which is intended to reduce trauma resulting from the tearing of tissue and expedite access to the pituitary gland.
As is well known by those of skill in the art, an innovative procedure has recently been developed for removing tumors from the pituitary gland of a patient. In accordance therewith, a microsurgical instrument and an endoscope are inserted through the patient's nostril, to reach the anterior wall of the sella which is located at the rear of the nasal cavity. A section of the sella, which is a thin layer of bone, is removed by means of endoscopic surgery to expose the tumor. Further endoscopic tasks are then performed, to remove the tumor. This procedure, whereby the tumor is accessed through a patient's nasal cavity, has proven to be much less traumatic than prior art techniques, and is described for example, in an article entitled "Endoscopic Endonasal Pituitary Surgery: Technical Aspects" by Dr. Hae-Dong Jho, one of the inventors herein, Contemporary Neurosurgery, Vol.19. No.6 (March 1997). The procedure is further described in "Endoscopic Pituitary Surgery", Jho et al, Neurosurgical Operative Atlas, Vol. 6 No.1(1996).
In the above procedure, a passage must be formed through the patient's nasal cavity as a necessary preliminary step. The nasal septum comprises a sheath-like barrier formed of cartilaginous and bony tissue, and is attached to the middle of the sphenoid sinus wall. Its attachment has to be broken, in order to access the sella and the tumor. The task of breaking the septum apart from the sphenoid sinus wall, in order to provide an opening therethrough, should ideally be done very quickly and very gently, to avoid tearing blood vessels and tissue and to thereby minimize trauma experienced by the patient.
In the past, a surgical tool or instrument has generally not been available which could perform the delicate task of properly breaking the nasal septum from the sphenoid sinus wall, and which at the same time was operable within the narrow confines of the nasal passage. Frequently, instruments used to detach the septum have not allowed a force to be applied, within the narrow boundaries of the nasal cavity, which was sufficient to abruptly or instantaneously break the septum free. Rather, the septum detachment procedure, using the available tools of the prior art, could require a period of thirty minutes or more. The total time for surgery, as well as fatigue experienced by the surgeon, were thereby significantly increased. Moreover, use of such prior art tools tended to increase traumatization and injury of the septum.